Common ethanol fuel mixtures
There are several common ethanol fuel mixtures in use around the world. The use of pure hydrous or anhydrous ethanol in internal combustion engines (ICE) is only possible if the engine is designed or modified for that purpose. Anhydrous ethanol can be blended with gasoline (petrol) in various ratios for use in unmodified gasoline engines, and with minor modifications can also be used with a higher content of ethanol. Ethanol fuel mixtures have "E" numbers which describe the percentage of ethanol fuel in the mixture by volume, for example, E85 is 85% anhydrous ethanol and 15% gasoline. Low ethanol blends, from E5 to E25, are also known as gasohol, though internationally the most common use of the term gasohol refers to the E10 blend. Blends of E10 or less are used in more than twenty countries around the world, led by the United States, where ethanol represented 10% percent of the U.S. gasoline fuel supply in 2011. See pp. 10. Blends from E20 to E25 have been used in Brazil since the late 1970s. E85 is commonly used in the U.S. and Europe for flexible-fuel vehicles. Hydrous ethanol or E100 is used in Brazilian neat ethanol vehicles and flex-fuel light vehicles and in hydrous E15 called hE15 for modern petrol cars in Netherlands. E10 or less E10, sometimes called gasohol, is a fuel mixture of 10% anhydrous ethanol and 90% gasoline that can be used in the internal combustion engines of most modern automobiles and light-duty vehicles without need for any modification on the engine or fuel system. E10 blends are typically rated as 2 to 3 octane higher than regular gasoline and are approved for use in all new US automobiles, and are mandated in some areas for emissions and other reasons.E10: Every vehicle's ethanol blend, drivingethanol.org. The E10 blend and lower ethanol content mixtures have been used in several countries, and its use has been primarily driven by the several world energy crises that have taken place since the 1973 oil crisis. Other common blends include E5 and E7. These concentrations are generally safe for recent engines that run on pure gasoline. As of 2006, mandates for blending bioethanol into vehicle fuels had been enacted in at least 36 states/provinces and 17 countries at the national level, with most mandates requiring a blend of 10 to 15% ethanol with gasoline. One way to measure alternative fuels in the US is the "gasoline-equivalent gallons" (GEG). In 2002, the U.S. used as fuel an amount of ethanol equal to 137,000 terajoules (TJ), the energy equivalent of 1.13 billion gallons (4.3 billion liters) of gasoline. This was less than 1% of the total fuel used that year.http://www.eia.doe.gov/cneaf/alternate/page/datatables/table10.html E10 and other blends of ethanol are considered to be useful in decreasing US dependence on foreign oil, and can reduce carbon monoxide (CO) emissions by 20 to 30% under the right conditions.Low-Level Ethanol Fuel Blends, Clean Cities fact sheet, April 2005. Although E10 does decrease emissions of CO and greenhouse gases such as CO2 by an estimated 2% over regular gasoline, it can cause increases in evaporative emissions and some pollutants depending on factors like the age of the vehicle and weather conditions.E10 Emissions, U.S. Department of energy. According to the Philippine Department of Energy, the use of not more than a 10% ethanol-gasoline mixture is not harmful to cars' fuel systems. Generally, automobile gasoline containing alcohol (ethanol or methanol) is not allowed to be used in U.S. certificated aircraft.Special Airworthiness Information Bulletin CE-07-06 (October 27, 2006), Federal Aviation Administration. Availability * E10 was introduced nationwide in Thailand, and replaced high octane pure gasoline in that country in 2007. fuel dispensers]] * E10 is also commonly available in the Midwestern United States. E10 has also been mandated for use in all standard automobile fuel in the state of Florida by the end of 2010.Florida E85 Laws and Incentives, U.S. Department of Energy. Due to the phasing out of MTBE as a gasoline additive and mainly due to the mandates established in the Energy Policy Act of 2005 and the Energy Independence and Security Act of 2007, ethanol blends have increased throughout the United States, and by 2009, the ethanol market share in the U.S. gasoline supply reached almost 8% by volume. MTBE & Ethanol, State of Texas Energy Conservation Office. * The Tesco chain of supermarkets in the UK have started selling an E5 brand of gasoline marketed as 99 RON super-unleaded. Its selling price is lower than the other two forms of high-octane unleaded on the market, Shell's V-Power (99 RON) and BP's Ultimate (97 RON). * Many petrol stations throughout Australia now also sell E10, typically at a few cents cheaper per litre than regular unleaded. It is more commonly found throughout the state of Queensland due to its large sugarcane farming regions. The use of E10 is also subsidised by the Queensland government. Some Shell service stations are also selling a 100 RON E5 blend called V-Power Racing (as opposed to the normal ethanol-free 98 RON V-Power). This is typically about 17 cents more expensive than regular unleaded. Many petrol stations no longer offer a "Regular 91" petrol option, instead only offering Regular E10 (91), Premium (95) and Premium (98). * In Sweden, all 95-octane gasoline is E5, while the status of 98-octane fuel is currently unclear. The product data sheets of the major fuel chains do not clearly state ethanol content of their 98-octane gasoline. In the early-mid 1990s, some fuel chains sold E10. * From January 2011, all 95 octane fuel in Finland is E10, and 98E5 octane fuel is also available. * Mandatory blending of ethanol was approved in Mozambique, but the percentage in the blend has not been specified. * South Africa approved a biofuel strategy in 2007, and mandated an 8% blend of ethanol by 2013. * A 2007 Uruguayan law mandates a minimum of 5% of ethanol blended with gasoline starting in January 2015.Ley Nº 18.195: Agrofuels (in Spanish) - Parliament of Uruguay. The monopolic, state-owned fuel producer ANCAP started blending premium gasoline with 10% of bioethanol in December 2009, which will be available in all the country by early January 2010.Ancap planea llevar de 2% a 5% mezcla con biodiesel - Diario El País, December 12, 2009 (in Spanish) The other two gasolines will follow later in 2010. *Dominican Republic has a mandate for blending 15% of ethanol by 2015. *Chile is considering the introduction of E5, and Bolivia and Venezuela of E10. A 2011 study conducted by VTT Technical Research Centre of Finland found there is practically no difference in fuel consumption in normal driving conditions between commercial gasoline grades 95E10 and 98E5 sold in Finland, despite the public perception that fuel consumption is significantly higher with 95E10. VTT performed the comparison test under controlled laboratory conditions and their measurements show that the cars tested used an average of of 95E10 per , as opposed to of 98E5 per . The difference was 0.07 in favor of 98E5 on average, meaning that using 95E10 gasoline, which has a higher ethanol content, increases consumption by 0.7%. When the measurements are normalized, the difference becomes 1.0%, a result that is highly consistent with an estimation of calorific values based on approximate fuel composition, which came out at 1.1% in favour of E5. E15 .]] E15 contains 15% ethanol and 85% gasoline. This is generally the highest ratio of ethanol to gasoline that is possible to use in vehicles recommended by auto manufacturers to run on E10 in the U.S. As a result of the Energy Independence and Security Act of 2007, which mandates an increase in renewable fuels for the transport sector, the U.S. Department of Energy began assessments for the feasibility of using intermediate ethanol blends in the existing vehicle fleet as a way to allow higher consumption of ethanol fuel. The National Renewable Energy Laboratory (NREL) conducted tests to evaluate the potential impacts of intermediate ethanol blends on legacy vehicles and other engines. In a preliminary report released in October 2008, the NREL presented the results of the first evaluations of the effects of E10, E15 and E20 gasoline blends on tailpipe and evaporative emissions, catalyst and engine durability, vehicle driveability, engine operability, and vehicle and engine materials. This preliminary report found that none of the vehicles displayed a malfunction indicator light as a result of the ethanol blend used; no fuel filter plugging symptoms were observed; no cold start problems were observed at and laboratory conditions; and as expected, all test vehicles exhibited a loss in fuel economy proportional with the lower energy density of ethanol, for example, with E20, the average reduction in fuel economy was 7.7% when compared to the miles per gallon achieved by the gasoline only (E0) test vehicles. NREL/TP-540-43543, ORNL/TM-2008/117 In March 2009 a lobbying group from the ethanol industry, Growth Energy, formally requested the U.S. Environmental Protection Agency (EPA) to allow the ethanol content in gasoline to be increased to 15 percent from 10 percent. Organizations doing such studies included the Energy Department, the State of Minnesota, the Renewable Fuels Association, the Rochester Institute of Technology, the Minnesota Center for Automotive Research, and Stockholm University in Sweden. In October 2010 the EPA granted a waiver to allow up to 15% of ethanol blended with gasoline to be sold only for cars and light pickup trucks with a model year of 2007 or later, representing about 15% of vehicles on the U.S. roads. In January 2011 the waiver was expanded to authorize use of E15 to include model year 2001 through 2006 passenger vehicles. The EPA also decided not to grant any waiver for E15 use in any motorcycles, heavy-duty vehicles, or non-road engines because current testing data does not support such a waiver. According to the Renewable Fuels Association the E15 waivers now cover 62% of vehicles on the road in the US, and the ethanol group estimates that if all 2001 and newer cars and pickups were to use E15, the theoretical blend wall for ethanol use would be approximately 17.5 billion gallons (66.2 billion liters) per year. EPA is still studying if older cars can withstand a 15 percent ethanol blend. As EPA waiver authorize but does not require stations to offer E15, a practical barrier to the commercialization of the higher blend is the lack of infrastructure, similar to the limitations suffered by sales of E85, as most fuel stations do not have enough pumps to offer the new blend, few existing pumps are certified to dispense E15, and there are no dedicated tanks readily available to store E15. Also some state and federal regulations would have to change before E15 can be legally sold. The National Association of Convenience Stores, which represents most gasoline retailers, considers that the potential for actual E15 demand is small “''because the auto industry is not embracing the fuel and is not adjusting their warranties or recommendations for the fuel type''." One possible solution to the infrastructure barriers is the introduction of blender pumps that allow consumers to turn a dial to select the level of ethanol, which would also allow owners of flexible-fuel cars to buy E85 fuel. In June 2011 EPA, in cooperation with the Federal Trade Commission, issued its final ruling regarding the E15 warning label that is required to be displayed in all E15 fuel dispensers in the U.S. to inform consumers about what vehicles can, and what vehicles and equipment cannot, use the E15 blend. Both the Alliance of Automobile Manufacturers and the National Petrochemical and Refiners Association complained that relying solely on this warning label is not enough to protect consumers from misfueling. hE15 hE15 contains 15% hydrous ethanol and 85% gasoline and has been introduced at public gas stations in Netherlands since 2008. Ethanol fuel specifications worldwide traditionally dictate use of anhydrous ethanol (less than 1% water) for gasoline blending. This results in additional costs, energy usage and environmental impacts associated with the extra processing step required to dehydrate the hydrous ethanol produced via distillation (3.5-4.9 vol.% water) to meet the current anhydrous ethanol specifications. A patented discovery reveals that hydrous ethanol can be effectively used in most ethanol/gasoline blending applications. According to the Brazilian ANP specification hydrous ethanol contains up to 4.9 vol.% water. In hE15 this would be up to 0.74 vol.% water in the overall mixture. Japanese scientific evidence reveals that water is an inhibitor for corrosion by ethanol. The experiments are done with E50, which is more aggressive & speeds up the corrosion effect. It is very clear that by increasing the amount of water in fuel ethanol one can reduce the corrosion. At 2% or 20,000 ppm water in the fuel ethanol the corrosion stopped. The observations in Japan are in line with the fact that hydrous ethanol is known for being less corrosive than anhydrous ethanol. The reaction mechanism is 3EtOH + Al -> Al(OEt)3 +3/2H2 will be the same at lower-mid blends. When enough water is present in the fuel, the aluminum will react preferably with water to produce Al2O2, repairing the protective aluminum oxide layer which is why the corrosion stops. The aluminum alkoxide does not make a tight oxide layer, which is why the corrosion continues. In other words water is essential to repair the holes in the oxide layer. Based on the Japanese results one could consider a minimum of 2% water content in fuel ethanol to enable E15 in regular non flex fuel vehicles. Water injection has additional positive effects on the engine performance (thermodynamic efficiency) and also reduces emissions. Overall, a transition from anhydrous to hydrous ethanol for gasoline blending is expected to make a significant contribution to ethanol’s cost-competitiveness, fuel cycle net energy balance, air quality and greenhouse gas emissions. The level of blending above 10 % (V/V) is chosen both from a technical (safety) perspective and to distinguish the product in Europe from regular unleaded petrol for reasons of taxes and customer clarity. Small scale tests have shown that many vehicles with modern engine types can run smoothly on this hydrous ethanol blend. Mixed tanking scenarios with anhydrous ethanol blends at 5% or 10% level do not induce phase separation. As avoiding mixing with E0, in particular at extremely low temperatures, in logistic systems and engines is not recommended, a separate specification for controlled usage is presented in a Netherlands Technical Agreement NTA 8115 (not published yet). The NTA 8115 is written for a worldwide application in trading and fuel blending. E20, E25 E20 contains 20% ethanol and 80% gasoline, while E25 contains 25% ethanol. These blends have been widely used in Brazil since the late seventies. As a response to the 1973 oil crisis, the Brazilian government made mandatory the blend of ethanol fuel with gasoline, fluctuating between 10% to 22% from 1976 until 1992. Ph.D. Dissertation Thesis, pp. 81-82 Due to this mandatory minimum gasoline blend, pure gasoline (E0) is no longer sold in Brazil. A federal law was passed in October 1993 establishing a mandatory blend of 22% anhydrous ethanol (E22) in the entire country. This law also authorized the Executive to set different percentages of ethanol within pre-established boundaries, and since 2003 these limits were fixed at a maximum of 25% (E25) and a minimum of 20% (E20) by volume. See article 9º and modifications approved by Law Nº 10.696, 2003-07-02 Since then, the government has set the percentage on the ethanol blend according to the results of the sugarcane harvest and ethanol production from sugarcane, resulting in blend variations even within the same year. Since July 1, 2007 the mandatory blend was set at 25% of anhydrous ethanol (E25) by Executive Decree, This decree fixed the mandatory blend at 25% startiting July 1st, 2007 and this has been the standard gasoline blend sold throughout Brazil most of the time as of 2011. However, as a result of a supply shortage and the resulting high ethanol fuel prices, in 2010 the government mandated a temporary 90-day blend reduction from E25 to E20 beginning February 1, 2010. As prices rose abruptly again due to supply shortages that took place again between the 2010-2011 harvest seasons, some ethanol had to be imported from the United States, and in April 2011 the government reduced the minimum mandatory blend to 18 percent, leaving the mandatory blend range between E18 to E25. All Brazilian automakers have adapted their gasoline engines to run smoothly with these range of mixtures, thus, all gasoline vehicles are built to run with blends from E20 to E25, defined by local law as "Common gasoline type C". See definition of "Gasolina A" and "Gasolina C". Some vehicles might work properly with lower concentrations of ethanol, however, with a few exceptions, they are unable to run smoothly with pure gasoline which causes engine knocking, as vehicles traveling to neighboring South American countries have demonstrated. Flexible-fuel vehicles, which can run on any mixed of gasoline E20-E25 up to 100% hydrous ethanol (E100 or hydrated ethanol) ratios, Onda dos flex pode gerar desequilíbrio com a gasolina|language=Portuguese}} were first available in mid 2003. In July 2008, 86% of all new light vehicles sold in Brazil were flexible-fuel, and only two carmakers build models with a flex-fuel engine optimized to operate with pure gasoline (E0): Renault with the models Clio, Symbol, Logan, Sandero and Mégane, and Fiat with the Siena Tetrafuel. Thailand introduced E20 in 2008, however, shortages in ethanol supplies by mid-2008 caused a delay in the expansion of the E20 fueling station network in the country. By mid 2010 there were 161 fueling stations selling E20 and sales have risen 80% since April 2009. The rapid growth in E20 demand is due to the fact that most vehicle models launched since 2009 were E20-compatible, and sales of E20 are expected to grow faster once more local automakers start producing small E20-compatible fuel-efficient cars. The Thai government is promoting ethanol usage through subsidies, as ethanol costs four baht a litre more than gasoline. A state law approved in Minnesota in 2005 mandates that ethanol comprise 20 percent of all gasoline sold in this American state beginning in 2013. Successful tests have been conducted to determined the performance under E20 by current vehicles and fuel dispensing equipment designed for E10. E70, E75 E70 contains 70% ethanol and 30% gasoline, while E75 contains 75% ethanol. These are the winter blends used in the United States and Sweden for E85 flexible-fuel vehicles during the cold weather, but still sold at the pump labeled as E85. The seasonal reduction of the ethanol content to a E85 winter blend is mandated to avoid cold starting problems at low temperatures. In the US this seasonal reduction of the ethanol content to E70 applies only in cold regions, where temperatures fall below during the winter. In Wyoming for example, E70 is sold as E85 from October to May. In Sweden, all E85 flexible-fuel vehicles use a E75 winter blend. This blend was introduced since the winter 2006-07 and E75 is used from November until March. For temperature below all E85 flex vehicles require an engine block heater to avoid cold starting problems. The use of this device is also recommended for gasoline vehicles when temperatures drop below . Another option when extreme cold weather is expected is to add more pure gasoline in the tank, thus reducing the ethanol content below the E70 winter blend, or simply not to use E85 during extreme low temperature spells. E85 blend.]] E85 is a mixture of 85% ethanol and 15% gasoline, and is generally the highest ethanol fuel mixture found in the United States and several European countries, particularly in Sweden, as this blend is the standard fuel for flexible-fuel vehicles. This mixture has an octane rating of about 105, which is significantly lower than pure ethanol but still higher than normal gasoline (87-95 octane, depending on country). for E85 fuel]] The 85% limit in the ethanol content was set to reduce ethanol emissions at low temperatures and to avoid cold starting problems during cold weather, at temperatures lower than . A further reduction in the ethanol content is used during the winter in regions where temperatures fall below and this blend is called Winter E85, as the fuel is still sold under the E85 label. A winter blend of E70 is mandated in some regions in the US, while Sweden mandates E75. As of October 2010 there were nearly 3,000 E85 fuel pumps in Europe, led by Sweden with 1,699 filling stations. The United States had 2,414 public E85 fuel pumps located in 1,701 cities by October 2010, mostly concentrated in the Midwest. Thailand introduced E85 fuel by the end of 2008, and by mid 2010 there were only four E85 filling stations, with plans to expand to 15 stations by 2012. ED95 ED95 designates a blend of 95% ethanol and 5% ignition improver and is used in modified diesel engines where high compression is used to ignite the fuel, as opposed to the operation of gasoline engines where spark plugs are used. This fuel was developed by Swedish ethanol producer SEKAB. Because of the high ignition temperatures of pure ethanol, the addition of ignition improver is necessary for successful diesel engine operation. The diesel engine that runs on ethanol has also a higher compression ratio and an adapted fuel system. .]] This fuel has been used with success in many Swedish Scania buses since 1985, which has produced around 700 ethanol buses, more than 600 of them to Swedish cities, and more recently has also delivered ethanol buses for commercial service in Great Britain, Spain, Italy, Belgium, and Norway. As of June 2010 Stockholm has the largest ethanol ED95 bus fleet in the world. As of 2010 the Swedish ED95 engines are in its third generation and already have complied with Euro 5 emission standards, without any kind of post-treatment of the exhaust gases. The ethanol-powered engine is also being certified as Environmentally Enhanced Vehicle (EEV) in the Stockholm municipality. The EEV rule still has no date to enter into force in Europe and is stricter than the Euro 5 standard. Report 2010-36-0130I, pp. 5 Nottingham became the first city in England to operate a regular bus service with ethanol-fueled vehicles. Three ED95 single-deck buses entered regular service in the city in March 2008. Soon after, Reading also introduced ED95 double-deck buses. Under the auspices of the BioEthanol for Sustainable Transport (BEST) project, more than 138 bioethanol ED95 buses were part of demonstration trial at four cities, three in Europe, and one in Brazil, between 2006 and 2009. A total of 127 ED95 buses operated in Stockholm, five buses operated in Madrid, three in La Spezia, and one in Brazil. In Brazil, the first Scania ED95 bus with a modified diesel engine was introduced as a trial in São Paulo city on December 2007, and since November 2009 there were two ED95 buses in regular service. The Brazilian trial project run for three years and performance and emissions were monitored by the National Reference Center on Biomass (CENBIO- ) at the Universidade de São Paulo. In November 2010 the municipal government of São Paulo city signed an agreement with UNICA, Cosan, Scania and Viação Metropolitana", a local bus operator, to introduced a fleet of 50 ethanol-powered ED95 buses by May 2011. Scania manufactures the bus engine and chassis in its plant located in São Bernardo do Campo, São Paulo, using the same technology and fuel as the ED95 buses already operating in Stockholm. The bus body is a Brazilian CAIO. The first ethanol-powered buses were delivered in May 2011, and the 50 buses will start regular service in June 2011 in the southern region of São Paulo. The 50 ED95 buses had a cost of R$ 20 million ( ) and due to the higher cost of the ED95 fuel and the lower energy content of ethanol as compared to diesel, one of the firms participating in the cooperation agreement, Raísen (a joint venture between Royal Dutch Shell and Cosan), supplies the fuel to the municipality at 70% of the market price of regular diesel. E100 ian 2008 Honda Civic flex-fuel has outside access to the secondary reservoir gasoline tank in the front right side shown by the arrow.]] E100 is pure ethanol fuel. Straight hydrous ethanol as an automotive fuel has been widely used in Brazil since the late seventies for neat ethanol vehicles and more recently for flexible-fuel vehicles. The ethanol fuel used in Brazil is distilled close to the azeotrope mixture of 95.63% ethanol and 4.37% water (by weight)which is approximately 3.5% water by volume. The azeotrope is the highest concentration of ethanol that can be achieved via distillation. The maximum water concentration according to the ANP specification is 4.9 vol.% (approximately 6.1 weight%) See Table I – Specifications for AEAC and AEHC at "Anexo: Regulamente Técnico ANP Nº 7/2005. The E nomenclature is not adopted in Brazil, but hydrated ethanol can be tagged as E100 meaning that it does not have any gasoline, because the water content is not an additive but rather a residue from the distillation process. However, straight hydrous ethanol is also called E95 by some authors. Here Brazilian flex cars are called E95 flexible-fuel vehicles. Here E95 is defined as pure ethanol before it is denatured, so straight hydrated ethanol would be E95 and not E100 by this definition. The first commercial vehicle capable of running on pure ethanol was the Ford Model T, produced from 1908 through 1927. It was fitted with a carburetor with adjustable jetting, allowing use of gasoline or ethanol, or a combination of both.Hunt, V, D, The Gasohol Handbook, Industrial Press Inc., 1981, pp 9, 420,421, 442 At that time, other car manufactures also provided engines for ethanol fuel use. Thereafter, and as a response to the 1973 and 1979 energy crises, the first modern vehicle capable of running with pure hydrous ethanol (E100) was launched in the Brazilian market, the Fiat 147, after testing with several prototypes developed by the Brazilian subsidiaries of Fiat, Volkswagen, General Motors and Ford. Since 2003, Brazilian newer flexible-fuel vehicles are capable of running on pure hydrous ethanol (E100) or blended with any combination of E20 to E25 gasoline Print edition No. 1941 (a mixture made with anhydrous ethanol), the national mandatory blend. E100 imposes a limitation on normal vehicle operation as ethanol's lower evaporative pressure (as compared to gasoline) causes problems when cold starting the engine at temperatures below . For this reason both pure ethanol and E100 flexible-fuel vehicles are built with an additional small gasoline reservoir inside the engine compartment to help in starting the engine when cold by initially injecting gasoline. Once started, the engine is then switched back to ethanol. An improved flex engine generation was developed to eliminate the need for the secondary gas tank by warming the ethanol fuel during starting, Ano 2, No. 3 (every article is presented in both English and Portuguese) and allowing flex vehicles to do a normal cold start at temperatures as low as , the lowest temperature expected anywhere in the Brazilian territory. Originally published in Revista Valor Econômico. The Polo E-Flex, launched in March 2009, was the first flex fuel model without an auxiliary tank for cold start. The warming system is called Flex Start and was developed by Robert Bosch GmbH. Swedish carmakers have developed ethanol only capable engines for the new Saab Aero X BioPower 100 Concept E100, with a V6 engine which is fuelled entirely by E100 bioethanol, and the limited edition of the Koenigsegg CCXR, a version of the CCX converted to use E85 or E100, as well as standard 98 octane gasoline, and currently the fastest and most powerful flexible fuel vehicle with its twin-supercharged V8 producing 1018 hp when running on biofuel, as compared to 806 hp on 91 octane unleaded gasoline. The higher fuel efficiency of E100 in high performance race cars resulted in Indianapolis 500 races in 2007 and 2008 being run on 100 percent fuel grade ethanol. Use limitations Modifications to engines The use of ethanol blends in conventional gasoline vehicles is restricted to low mixtures, as ethanol is corrosive and can degrade some of the materials in the engine and fuel system. Also, the engine has to be adjusted for a higher compression ratio as compared to a pure gasoline engine in order to take advantage of ethanol’s higher oxygen content, thus allowing an improvement in fuel efficiency and a reduction of tailpipe emissions. The following table shows the required modifications to gasoline engines to run smoothly and without degrading any materials. This information is based on the modifications made by the Brazilian automotive industry at the beginning of the ethanol program in that country in the late seventies, and reflects the experience of Volkswagen do Brasil. Other disadvantages Disadvantages to ethanol fuel blends when used in engines designed exclusively for gasoline include lowered fuel mileage, metal corrosion, deterioration of plastic and rubber fuel system components, clogged fuel systems, fuel injectors, and carburetors, delamination of composite fuel tanks, varnish buildup on engine parts, damaged or destroyed internal engine components, water absorption, fuel phase separation, and shortened fuel storage life.Is fuel with an increased level of ethanol a problem for small gas engines?, Tools & Power Equipment, Consumer Reports, 24 June 2009Vatalaro, Michael,A Serious Problem - A Corny Solution, Boat US Magazine, (July 2006)Maloney, William,Ethanol Pros & Cons in Automotive Gas, retrieved 8 August 2011 Many major auto, marine, motorcycle, lawn equipment, generator, and other internal combustion engine manufacturers have issued warnings and precautions about the use of ethanol-blended gasolines of any type in their engines, and the Federal Aviation Administration and major aviation engine manufacturers have prohibited the use of automotive gasolines blended with ethanol in light aircraft due to safety issues from fuel system and engine damage.FAA to STC Holders: No Ethanol in Auto Fuel, EAA, retrieved 8 August 2011 See also * Ethanol fuel * Ethanol fuel in Brazil * Ethanol fuel in Sweden * Ethanol fuel in the United States Notes References External links * Bioenergywiki: Renewable fuel targets at bioenergywiki. See here a complete list of mandatory blends that will go into effect in several countries and regions on 2010 and thereafter * 2011 NACS Annual Fuels Report Category:Ethanol fuel Category:Petroleum products